Data Streaming API

The Data Streaming API pushes real-time market data using the MQTT protocol (v3.1.1) over TCP/IP or WebSocket. Use it to receive live quotes, snapshots, and tick data as they happen.

For on-demand HTTP queries, see Data API.

SDK Users

The Webull SDK handles MQTT connection, authentication, and message parsing automatically. See the real-time streaming example in Getting Started. The steps below are for manual integration without the SDK.

Supported Data

Market	Categories
United States	Stocks, ETFs, Futures, Crypto, Event Contracts

Data Type	Description
QUOTE	Real-time order book
SNAPSHOT	Market snapshot
TICK	Tick-by-tick transaction details

Step 1: Establish an MQTT Connection

Connection Endpoints

Environment	Protocol	Endpoint
Production	TCP/IP	data-api.webull.com:1883
Production	WebSocket	wss://data-api.webull.com:8883/mqtt

MQTT Client Libraries

• Python
• Java
• JavaScript
• Golang
• More languages

CONNECT Packet Fields

Field	Value
ClientId	A unique session_id you create (also used for subscribe/unsubscribe calls)
User Name	Your App Key
Password	Any value

Connection Rules

• Do not reuse the same session_id across multiple connections under one App Key. A new connection with the same session_id will disconnect the previous one.
• Each App Key supports a maximum of 5 concurrent connections. Exceeding this returns error code 105.
• After disconnecting, the server retains connection state for about 1 minute. If you've reached 5 connections, wait 1 minute before reconnecting.
• The server pushes messages at a maximum rate of 3 times per second per connection.

Connection Error Codes

Code	Description
0	Connection accepted
1	Unacceptable protocol version
2	Invalid ClientId
3	App Key is empty
7	Connection lost
16	Heartbeat timeout
100	Unknown error
101	Internal error
102	Connection already authenticated
103	Authentication failed
104	Invalid App Key
105	Exceeds connection limit

Step 2: Subscribe to Market Data

After establishing the MQTT connection, use the HTTP API to manage subscriptions:

• Subscribe — Start receiving real-time data for specified symbols
• Unsubscribe — Stop receiving data for specified symbols

caution

If the connection is dropped due to network issues, previous subscriptions are not automatically restored. You must re-subscribe after reconnecting.

Step 3: Parse Incoming Messages

Each message pushed from the server contains:

• Topic — Identifies the data type
• Payload — The actual data, serialized using Protocol Buffers or JSON

Topic-to-Payload Mapping

Data Type	Topic	Payload Format	Description
QUOTE	quote	Protobuf	Real-time order book
QUOTE	event-quote	Protobuf	Event contract order book
SNAPSHOT	snapshot	Protobuf	Market snapshot
SNAPSHOT	event-snapshot	Protobuf	Event contract snapshot
TICK	tick	Protobuf	Tick-by-tick details
NOTICE	notice	JSON	Server notifications
ECHO	echo	Null	Online check (heartbeat)

Protobuf Message Definitions

Basic (shared by all types)

message Basic {
    string symbol = 1;
    string instrument_id = 2;
    string timestamp = 3;
}

Quote (Real-time Order Book)

message Quote {
    Basic basic = 1;
    repeated AskBid asks = 2;
    repeated AskBid bids = 3;
}

message AskBid {
    string price = 1;
    string size = 2;
    repeated Order order = 3;
    repeated Broker broker = 4;
}

message Order {
    string mpid = 1;
    string size = 2;
}

message Broker {
    string bid = 1;
    string name = 2;
}

Snapshot (Market Snapshot)

message Snapshot {
    Basic basic = 1;
    string trade_time = 2;
    string price = 3;
    string open = 4;
    string high = 5;
    string low = 6;
    string pre_close = 7;
    string volume = 8;
    string change = 9;
    string change_ratio = 10;
    string ext_trade_time = 11;
    string ext_price = 12;
    string ext_high = 13;
    string ext_low = 14;
    string ext_volume = 15;
    string ext_change = 16;
    string ext_change_ratio = 17;
    string ovn_trade_time = 18;
    string ovn_price = 19;
    string ovn_high = 20;
    string ovn_low = 21;
    string ovn_volume = 22;
    string ovn_change = 23;
    string ovn_change_ratio = 24;
}

Tick (Tick-by-Tick Detail)

message Tick {
    Basic basic = 1;
    string time = 2;
    string price = 3;
    string volume = 4;
    string side = 5;
}

Event Quote

message EventQuote {
    Basic basic = 1;
    repeated EventAskBid yes_bids = 2;
    repeated EventAskBid no_bids = 3;
}

message EventAskBid {
    string price = 1;
    string size = 2;
}

Event Snapshot

message EventSnapshot {
    Basic basic = 1;
    string price = 2;
    string volume = 3;
    string last_trade_time = 4;
    string open_interest = 5;
    string yes_ask = 6;
    string yes_bid = 7;
    string yes_ask_size = 8;
    string yes_bid_size = 9;
    string no_ask = 10;
    string no_bid = 11;
    string no_ask_size = 12;
    string no_bid_size = 13;
}

Notification (JSON)

{
  "type": "status",
  "rtt": 100,
  "drop": 0,
  "sent": 0
}

What's Next

Once your MQTT connection is live and subscriptions are active, you'll receive real-time market data as it happens. For a complete working example using the SDK, check the Market Data API Getting Started guide.

If you run into issues with connections or data delivery, see Additional Resources for support channels.